A variety of structures are routinely inspected to determine the health of the structure and to identify any issues that may require further inspection, maintenance or repair. For example, buildings, bridges and the like may be regularly inspected to identify the onset of any issues that may potentially weaken or otherwise eventually render the structure unsuitable for its intended use. Similarly, vehicles, such as airplanes, trains, ships and the like, may be regularly inspected in order to similarly identify any issues that merit further inspection, maintenance or repair.
For example, commercial aircraft may be subject to periodic scheduled inspections. During these inspections, the aircraft must generally be removed from service to permit an intensive visual inspection of the aircraft to be conducted. In this regard, at least some aircraft inspections involve substantial disassembly of the aircraft in order to visually inspect the various components. For example, substantial disassembly of an aircraft may be required in order to inspect for corrosion damage and/or to identify crack propagation in regions of the aircraft that have limited accessibility.
By way of further example, the metallic floor structures supporting the main cabin floor beneath the galleys, lavatories and in the immediate proximity to the passenger entry and service doors are considered wet areas of the cabin floor because of their potential exposure to moisture, such as in the event of inclement weather as well as during normal passenger food and beverage service. The flooring in these wet areas is sealed in order to prevent moisture on the upper surface of the floor from penetrating through the floor into the floor support structure where the moisture may cause the floor support structure to corrode. In this regard, corrosion of the floor support surface is desirably avoided as the floor support structure includes, among other structural elements, the metallic floor beams, which are primary load bearing elements of the aircraft structure.
In order to visually inspect the floor support structure, cabin equipment including seats, floor coverings, galleys and lavatories must generally be removed. In addition, the sealed cabin floor panels must then be removed to expose the upper portions of the floor support structure. As will be recognized, the time and effort that will be required in order to visually inspect the floor support surface may be substantial, thereby potentially requiring the aircraft to remain out of service for a substantial period of time. Additionally, the removal of the cabin floor panels breaks the seal with which the floor panels had previously been secured to the floor support surface and it may prove difficult, if not impossible, to reseal the floor with at least the same degree of integrity as the floor was sealed during the original manufacture of the aircraft. Additionally, as with any inspection that requires substantial disassembly, the disassembly itself may accidentally damage the structure and/or the removed component such that additional maintenance or repair activities are required.
As noted above, another structural component that may be periodically inspected is the cutouts in the pressurized fuselage, such as cutouts in the crown section of the fuselage to accommodate antennas. As with the floor support structure, significant disassembly may be required in order to remove those portions of the cabin interior that are necessary in order to visually inspect the fuselage cutouts, as well as the reinforcing doublers that are attached to the fuselage skin panel about the fuselage cutouts by a plurality of fasteners.
In addition to the time and effort required to conduct a visual inspection, reliance upon scheduled inspections may be disadvantageous in that scheduled inspections may occur and may require the aircraft to be temporarily taken out of service in instances in which the aircraft has no structural issues and is determined not to be in need of any repair. Conversely, a scheduled inspection may occur later than desired in other instances in which a structural issue has developed and the lapse of the time that occurs between scheduled inspection is such that the structural issue is allowed to propagate or otherwise damage the surrounding structure such that more extensive repairs are required than if the structural issue had been identified soon after its inception.
It would therefore be desirable to provide improved techniques for inspecting a structure such that the inspection may be conducted efficiently, cost effectively and in a timely manner. In this regard, it would be desirable to provide improved inspection techniques for identifying cracks, moisture ingress or other structural issues in a timely fashion following the inception of the structural issues, while not requiring a structure to be removed from service for a prolonged period in order to be inspected in instances in which the structural issues have not yet arisen. Additionally, it would be desirable to provide an improved technique for inspecting structures which reduces the disassembly otherwise required for conventional visual inspection.